I am working on a sculpture that includes three servos, 4 x 12v motors, and 30 LED's. The three servos are running well on a 6v/1.5 amp wall wart. The additional three motors (12v, 500 mA each) will be ready for testing in a few day. Ideally, I would like to use a single power supply for the entire project. Something ready made wold be great but I see no Wall Wart rated more than 2 Amp. Is there something salvageable? If not, do I have to order a transformer, rectify it from scratch? If the total is 5 amps, do I make a rail and regulate with 78-- or LM317?

Are the DC to DC converters you describe the same as "buck converters? I am looking at tutorials to understand your suggestion. Are these circuits or a single component?

DC-DC converters is a common name for step-up, step-down, boost and buck-boost converters.Sometimes it is a small black box (with the components inside), but mostly it is a circuit board.Some examples: http://www.ebay.com/sch/i.html?_nkw=dc+dc+converter

To be sure I understand; I could use this http://www.ebay.ca/itm/For-12-Volt-5-Amp-12V-5A-DC-Supply-AC-Power-Adapter-LCD-SHIP-FROM-USA-/181046745793?pt=US_Monitor_Power_Supplies&hash=item2a273a1ac1&_uhb=1#ht_2455wt_945 and regulate with two or three of these DC to DC http://www.ebay.ca/itm/5pcs-DC-DC-Buck-Converter-Step-Down-Module-LM2596-Power-Supply-Output-1-23V-30V-/271091022746#ht_1777wt_702?

I have doubts about the first one (switching power supply 12Volt 5 Amp). I bought a few switching power supplies from Ebay, and most of them can not deliver the current and they get overheated and get broken within a few month.

If you would also use a DC-DC converters for the motors, you don't need a regulated power supply. Perhaps you have some DC power supply already ? Or an adaptor of 19V for a laptop.

Did you look at mpja.com at all?They have high current suppllies available.You could use a 12V, 4A supply and use smaller switching adapters for the lower voltageshttp://www.pololu.com/catalog/category/84

The first one depends on the motors. For an unregulated power supply I would prefer to use 15...25 V, and use DC-DC converters to make a good 12V for the motors.The second one is a brandless cheap switching power adapter again. If you buy that, you probably have to buy a better version soon. Don't try to buy a good 12V 4A power supply for 10 dollars, that's not possible.

If you want something cheap, this one: http://www.mpja.com/12-Volt-Power-Supply-85A-100W-Switching-Hengfu/productinfo/16013%20PS/But I'm not sure how it will behave without any load.

If you want something better: http://www.mpja.com/12-Volt-Power-Supply-51A-Linear-IHN12-51/productinfo/6609%20PS/

Sorry, a dumb question: What happens to the unused amps? Any problem running these motors directly from the power supply? Can both current and voltage be adjusted? I have ordered DC to DC converters. Thank you so much for the advice. The typical small, Arduino board driven projects I have worked with before have not been so challenging in terms of power supply.